1. Field of the Invention
This invention relates generally to internal combustion engines and, in particular, to electromagnetically actuated valve configurations.
2. Description of Related Art
Conventional internal combustion engines include a series of intake and exhaust valves which open and close in a proper sequence and at appropriate times. This opening and closing action allows an air/fuel mixture to be injected into the cylinders, and allows exhaust gases to be expelled from the cylinders. In order to cause the valves to open and close in the proper sequence and at appropriate times, these conventional engines have required complex mechanical arrangements. A sample mechanical arrangement would include gears, camshafts, crankshafts, and timing chains and require precise manufacturing to ensure proper timing between the crankshaft and the camshaft. Further, the interaction in this mechanical arrangement is critical because the cylinders must receive the air/fuel mixture, compress the mixture, ignite the compressed mixture, and expel resulting exhaust gases in a certain timed sequence. Timing is therefore critical to ensure proper and efficient operation. Also, the valve openings included in these arrangements are usually of limited size. The area opening to the cylinder is critical for engine efficiency and operation. The more air/fuel that is allowed into the cylinder bore and the more exhaust gas that is allowed to exit the cylinder bore, the engine will have more power output and efficient operation. To increase the valve opening area, four valve per cylinder engines have evolved. Although these four valve per cylinder engines do increase the surface area for gas to flow in and out of the cylinder bore over conventional two valve per cylinder engines, the geometry of positioning circular openings within the cross-sectional area of the cylinder limits the maximum size of the input and exhaust ports. The mechanical valve movement arrangement will conventionally include the camshaft, which is tied to the crank by means of a timing chain. The camshaft has a series of cam lobes, which raise and lower a push rod, or in overhead cam engines, open or close a valve. The push rods are linked to rocker arms and lifters so that as the cam turns, the lifter rides up on the cam lobe to cause the push rod to move in the upward and downward direction. The rocker arm is pivotally mounted to the head with the push rod pressing at one end of the rocker arm and the other end of the rocker arm pressing against the valve stem so that the motion of the push rod is transferred to cause the valve to move. On an overhead cam engine, the cam lobe contacts the valves directly, and no push rod, lifter, or rocker arm is necessary. The valves on both types of engines are fitted with springs which act to open and close the valve in response to rotation of the associated lobe on the camshaft. These springs often have a compression resistance in excess of 300 pounds.
However, this invention employs electric actuators which may be electric solenoids, to open and close nested valves and has several distinctive advantages. First, unlike the prior art, there are no timing chains, timing gears, push rods, camshafts, lifters, rockers, or high resistance valve springs needed. Hence, the results of this invention are less weight, less friction, less failure of parts, less resistance, less adjustments etc.
Second, the valve assembly may be of nested orientation and thus the entire surface area of the cylinder opening can be utilized to maximize power and efficiency.
Third, although some new inventions shift the relationships between the crankshaft and camshaft, the shifting is in a limited manner. Also, most art in this field involves a fixed relationship between the crankshaft and the camshaft by way of a timing chain and timing gears. The crankshaft turns the camshaft; the camshaft has fixed cam lobes--or a "grind," which controls when the valve opens, how wide, and for how long. Therefore, the relationship between the crankshaft and the valves is fixed and cannot be varied. However, this invention provides a system which has infinitely variable control of these items. Infinite variable control is very desireable because engine performance can be optimized under varying conditions. One needs only to look at how many different camshaft "grinds" that are available to appreciate the value of a variable control between the crankshaft and the valves.